The necessary significance of abnormal lipoprotein values in uremia and associated coronary heart disease in patients with ESRD cannot be demonstrated by regular cholesterol measurement. Therefore, it was stated that a specific method based on LDL cholesterol, HDL-cholesterol, and triglycerides should be developed to identify kidney patients with high cardiovascular risk requiring lipid-lowering treatment
7.
Uremia is considered to be an indicator of the activated acute phase response. Increased levels of IL-6 and CRP in serum are thought to be predictors of cardiovascular mortality in hemodialysis patients. Some acute phase proteins such as fibrinogen and lipoprotein a, known determinants of coronary artery diseases, are elevated in plasma in hemodialysis patients in this current inflammatory condition 8.
Serum TG levels increase due to the production and storage of TG-rich lipoproteins such as VLDL in ESRD. In parallel with this, components of high-TG lipoproteins, such as apoB, apoC-III and apo-E, are found at a high concentration in ESRD. On the other hand, levels of a number of antiatherogenic markers are reduced, especially where low HDL-cholesterol and apoA-I levels are most noticeable 9.
Combined hyperlipidemia (high cholesterol and triglycerides) with low HDL-cholesterol levels reflects a higher atherogenic event than isolated LDL cholesterol elevation. Studies have shown that cholesterol ester transfer from HDL decreases in hemodialysis patients, resulting in impaired reverse cholesterol transport. Individuals with high TG levels appear to have high-risk lipoprotein subclass profiles that worsen if they have underlying diabetes mellitus. Oxidized lipoproteins can affect endothelial vasodilation and vascular apoptotic cell death through stimulation of O2 formation 10.
Patients with ESRD are at high risk not only for decreased renal function but also for the development of atherosclerosis due to changes in lipid metabolism. Therefore, these high-risk patients should be identified, and their cardiovascular mortality should be reduced with adequate lipid-lowering treatment as there is evidence of the effectiveness of lipid reduction in reducing cardiovascular mortality 11.
Small dense LDL-cholesterol (sdLDL-C) levels were monitored for four years and fifty-four cardiovascular events were detected in a retrospective study including one hundred and forty-five patients with ESRD. A strong correlation was found between sdLDL-C and cardiovascular disease risk in patients with ESRD as a result of this study 12.
77.762 (85.6%) of the patients were grouped as having myocardial infarction without coronary artery disease and 13.033 (14.4%) as having myocardial infarction due to coronary artery disease in a study involving 90.795 hemodialysis patients. Hypercholesterolemia was shown to be closely associated with increased mortality in the myocardial infarction group without coronary artery disease according to this study 13.
The causes of increased serum TG/HDL-C ratio and its association with cardiovascular mortality were investigated in a study including approximately 50.000 hemodialysis patients with ESRD. This study showed that increased TG/HDL-C ratios predicted negative cardiovascular disease outcomes in individuals with chronic renal failure 14.
TG/HDL-C ratio is a reliable and easily accessible marker to evaluate cardiovascular mortality and survival in patients without diabetes 15. 60% of deaths occurred during the 4-year follow-up period due to cardiovascular disease, and high serum TG/HDL-C ratios have been shown to be associated with increased risk of cardiovascular disease mortality and all mortality causes in peritoneal dialysis patients in a study on 1.170 patients with CKD undergoing peritoneal dialysis 16.
In a study involving 7.000 patients diagnosed with acute myocardial infarction, the TG/HDL-C ratio was compared, and the patients were divided into three groups according to glomerular filtration rate (GFR). Major cardiovascular events were recorded in 593 patients during the one-year follow-up. A significant correlation was found between TG/HDL-C ratio and major cardiovascular diseases (such as cardiac death, myocardial infarction, repeated percutaneous coronary intervention) in the entire study group. When kidney functions were examined afterwards, renal function was found to be significantly correlated with high TG/HDL-C ratio and cardiovascular events in patients with normal renal function and mild renal dysfunction. TG/HDL-C ratio has been reported to be an easy-to-use and independent predictor for one-year follow-up in patients with acute myocardial infarction 17.
As a result, chronic renal failure is a very common condition worldwide. It is thought that it will be the main cause of morbidity and mortality in subsequent decades. TG/HDL-cholesterol ratio can be used as a cheap, reproducible predictor of cardiovascular mortality, particularly due to CKD. TG/HDL-cholesterol ratio was found to be higher especially in patients with CKD not undergoing dialysis compared to chronic kidney patients undergoing dialysis and healthy control group. In conclusion, it can be said that dialysis in CKD leads to a decrease in cardiovascular mortality even though the mechanism is not clear according to these results, and we need a large number of clinical studies on this subject that cover a wide range of patients.